U.S. patent application number 12/866459 was filed with the patent office on 2012-05-10 for vehicle body components with a metal hybrid construction and production methods thereof.
This patent application is currently assigned to Leonid Levinski. Invention is credited to Asa Bengtsson, Martin Brodt, Michael Fuetterer, Alfons Honsel, Alexandree Ivlev, Igor Kireev, Leonid Levinski, Victor Samoilov.
Application Number | 20120112486 12/866459 |
Document ID | / |
Family ID | 40417622 |
Filed Date | 2012-05-10 |
United States Patent
Application |
20120112486 |
Kind Code |
A1 |
Fuetterer; Michael ; et
al. |
May 10, 2012 |
VEHICLE BODY COMPONENTS WITH A METAL HYBRID CONSTRUCTION AND
PRODUCTION METHODS THEREOF
Abstract
Method for manufacturing a zinc-coated nonferrous metal
component for the production of a corrosion-protected vehicle body
in a mixed construction includes providing an untreated nonferrous
metal component and applying a coating by zinc diffusion onto the
nonferrous metal component. A zinc dust mixture is diffused at a
temperature of from 300 to 600.degree. C. so as to form a zinc
diffusion layer.
Inventors: |
Fuetterer; Michael;
(Hildrizhausen, DE) ; Honsel; Alfons; (Grafenau,
DE) ; Bengtsson; Asa; (Stuttgart, DE) ;
Levinski; Leonid; (Brussels, BE) ; Samoilov;
Victor; (Brussels, BE) ; Brodt; Martin; (Weil
der Stadt, DE) ; Ivlev; Alexandree; (Gages, BE)
; Kireev; Igor; (Uccle, BE) |
Assignee: |
Leonid Levinski
Brussels
BE
|
Family ID: |
40417622 |
Appl. No.: |
12/866459 |
Filed: |
November 25, 2008 |
PCT Filed: |
November 25, 2008 |
PCT NO: |
PCT/EP08/09959 |
371 Date: |
March 4, 2011 |
Current U.S.
Class: |
296/1.01 ;
427/328; 72/47 |
Current CPC
Class: |
B23K 2103/20 20180801;
B23K 2103/24 20180801; C23C 10/02 20130101; B23K 2101/34 20180801;
C23C 10/28 20130101; C23C 10/36 20130101; B23K 2103/22 20180801;
B23K 2101/006 20180801 |
Class at
Publication: |
296/1.01 ;
427/328; 72/47 |
International
Class: |
B62D 39/00 20060101
B62D039/00; B21D 31/00 20060101 B21D031/00; B05D 7/14 20060101
B05D007/14; B05D 3/00 20060101 B05D003/00; B05D 3/10 20060101
B05D003/10 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 7, 2008 |
DE |
10 2008 007 977.4 |
Claims
1-13. (canceled)
14. A method for manufacturing a zinc-coated nonferrous metal
component for the production of a corrosion-protected vehicle body
in a mixed construction, the method comprising: providing an
untreated nonferrous metal component; and applying a coating by
zinc diffusion onto the nonferrous metal component, wherein a zinc
dust mixture is diffused at a temperature of from 300 to
600.degree. C. so as to form a zinc diffusion layer.
15. The method as recited in claim 14, wherein the nonferrous metal
is a light metal alloy on the basis of an Al-, Ti- or Mg-alloy.
16. The method as recited in claim 15, wherein the light metal
alloy has an Al content >55% by weight.
17. The method as recited in claim 14, further comprising cleaning
oxides from a surface of the untreated nonferrous metal component
and activating the surface prior to applying the coating.
18. The method as recited in claim 14, further comprising applying
a phosphating layer onto the zinc diffusion layer.
19. The method as recited in claim 14, wherein the at least one
nonferrous metal includes at least one of copper and a copper
alloy.
20. The method as recited in claim 14, wherein the untreated
nonferrous metal component is provided as a sheet metal, and
further comprising molding the nonferrous metal component after
applying the coating.
21. The method as recited in claim 14, further comprising
after-treating by thermoforming in air the nonferrous metal
component, wherein the nonferrous metal component comprises at
least one of Al-, Ti- and an Mg-alloy.
22. A vehicle body component comprising at least one light metal
component joined to a steel component, wherein the light metal
component has a zinc diffusion layer configured to prevent an
immediate contact between light metal and steel in a joining
region.
23. The vehicle body component as recited in claim 22, wherein the
steel component is zinc-coated.
24. The vehicle body component as recited in claim 23, wherein the
steel component is hot-galvanized.
25. The vehicle body component as recited in claim 22, wherein at
least in an area of the joining region, the vehicle body component
has a lacquer layer applied directly onto metal surfaces or onto a
phosphating layer disposed on the metal surfaces.
26. The vehicle body component as recited in claim 25, wherein the
lacquer layer is a KTL coating.
27. The vehicle body component as recited in claim 22, wherein the
light metal component and the steel component are joined by at
least one weld.
28. Method of using a vehicle body component in a motor vehicle, in
a metal hybrid construction or a mixed construction, the method
comprising: providing a vehicle body component comprising at least
one light metal component joined to a steel component, wherein the
light metal component has a zinc diffusion layer configured to
prevent an immediate contact between the light metal and the steel
in a joining region; and incorporating the vehicle body component
in the motor vehicle, in the metal hybrid construction or in the
mixed construction.
Description
CROSS REFERENCE TO PRIOR APPLICATIONS
[0001] This application is a U.S. National Phase application under
35 U.S.C. .sctn.371 of International Application No.
PCT/EP2008/009959, filed on Nov. 25, 2008 and which claims benefit
to German Patent Application No. 10 2008 007 977.4, filed on Feb.
7, 2008. The International Application was published in German on
Aug. 13, 2009 as WO 2009/097882 A1 under PCT Article 21(2).
FIELD
[0002] The present invention provides a method for manufacturing
zinc-coated components from nonferrous metals, for example, from
light metal alloys such as Al-, Ti- or Mg-alloys or copper and Cu
alloys, by means of thermal diffusion. The present invention
further provides vehicle body components in metal hybrid
construction or mixed construction made of steel and of light metal
coated with Zn by thermal diffusion which have improved corrosion
protection.
BACKGROUND
[0003] In the manufacturing of vehicles, the aspect of lightweight
design has led to increasing use of hybrid constructions for the
vehicle body. Typical variants in this regard are components of the
outer skin of the vehicle body which are made of a light-weighted
metallic material (for example, an aluminum alloy), optionally with
reinforcement members of steel material, and which are arranged on
steel frame constructions. Alternatively, as described, for
example, in DE 198 24 932 A1, the outer skin component can consist
of sheet metal while the reinforcement member is made of a light
metal alloy. Further, the frame construction (such as the space
frame) can be realized in mixed construction. DE 10 2004 004 386
describes examples of mixed construction of covering parts for use
as components of the vehicle body.
[0004] For lightweight design, use is made of lightweight metallic
materials, for example, Al alloys, which have distinctly lower
corrosion rates than steels. In this case, the light metals will
normally not require a special anti-corrosion layer. In practice,
however, the composite material comprising the electrochemically
base light metal alloys and the low-alloy steels commonly used in
the construction of car bodies will cause corrosion problems due to
the different electrochemical potentials of the materials.
[0005] For this reason, contact or joint regions between the
different materials require considerable expenditure to protect
them from contact corrosion. This holds true, for example, for
vehicle bodies which are typically exposed to an ingress of
corrosive aqueous media. In this regard, a typical measure in
vehicle construction is seam sealing wherein a special plastic
sealing is applied on the joint seam between the two materials.
[0006] When connecting the joints, use must frequently be made of
bonding so as to prevent direct electrochemical contact between the
different materials. This is described, for example, in DE 19939977
A1.
[0007] A further composite material which causes problems due to
contact corrosion is a mixed construction of steel and copper. In
such a construction, the Cu alloy, when compared to the steel, is
the more precious component. Here the contact site must also be
protected against the formation of a local element by use of
special measures.
[0008] With regard to the demands on reliable and inexpensive
corrosion protection, for example, in the regions of joints, the
known techniques and methods for manufacturing vehicle body
components or the basic structure of the vehicle body by utilizing
mixed-construction technology are, now as before,
unsatisfactory.
SUMMARY
[0009] An aspect of the present invention is to provide a
component, for example, a vehicle body component for motor
vehicles, in mixed construction made of steels and light metal
alloys or copper alloys, which component provides improved
corrosion resistance in the joint regions. A further aspect of the
present invention is to provide a method for providing suitable
components of nonferrous metal for such mixed-construction
designs.
[0010] In an embodiment, the present invention provides a method
for manufacturing a zinc-coated nonferrous metal component for the
production of a corrosion-protected vehicle body in a mixed
construction which includes providing an untreated nonferrous metal
component and applying a coating by zinc diffusion onto the
nonferrous metal component. A zinc dust mixture is diffused at a
temperature of from 300 to 600.degree. C. so as to form a zinc
diffusion layer.
DETAILED DESCRIPTION
[0011] A thermal diffusion method, hereunder referred to as a zinc
diffusion method or a zinc thermodiffusion method, is provided as a
method for manufacturing zinc-coated components from nonferrous
metals, for example, for the production of corrosion-protected
vehicle bodies in mixed construction. Concerning the zinc diffusion
method, use is made of already-existing thermal diffusion methods
for the Zn coating of ferrous metals or steels. These methods are
in principle based on the sherardizing method for steel materials
as described in DIN EN 13811, which is known for use in small parts
and bulk material. In sherardizing, the small parts are heated in
close contact with zinc dust and with an inert filler material such
as, for example, sand, thereby initiating a solids diffusion of the
Zn into the steel surface. By sherardizing, a coating of a
zinc-iron alloy and, respectively, different intermetallic Fe-Zn
phases are generated on the components. A suitable base material
for the iron as described in DIN EN 13811 includes unalloyed carbon
steels or weakly alloyed steels.
[0012] Additional variants of this thermal diffusion method for
steels are described, for example, in DE 103 48 086 A1, RU 2 174
159, DE 10 2004 035 049 B4 or UA 75728 for the coating of steel
substrates.
[0013] DE 103 48 086 A1 describes that a thermoformed and hardened
component of high-strength steel is to be provided with a corrosion
protection layer comprising a zinc-iron alloy that is to be applied
by use of a method for the diffusion of solids. DE 103 48 086 A1
describes using a sherardizing method in a modified form for
heat-transfer-sensitive hardened vehicle components.
[0014] RU 2 174 159 describes a method wherein the steel component
and a saturation mixture containing 80 to 90% of zinc are treated
in a tightly sealed rotating container at a temperature of 360 to
470.degree. C. with permanent rotation.
[0015] DE 10 2004 035 049 B4 describes a method for Zn for the
coating of steel products, such as products made of high-strength
steels and products which are molded only with difficulties, by
thermal treatment in a container into which the component is
inserted simultaneously with a finely dispersed zinc powder and a
heat-stabilizing filling material in the form or granules or
pellets. The thermal diffusion coating is performed at a
temperature of 260 to 320.degree. C.
[0016] According to an embodiment of the present invention, the
nonferrous metal used is a light metal alloy on the basis of an
Al-, Ti- or Mg-alloy, or a Cu alloy.
[0017] Surprisingly, after suitable adaptation of temperature
control and treatment intensity, the above described methods for
the coating of ferrous metal and for the coating of steel can
respectively be transferred in an analogous manner to the
respective to-be-coated metal on the basis of an Al-, Mg-, Ti- or
Cu alloy. For light metal alloys, use can be made of alloys
normally employed for construction tasks. According to the present
invention, the process of applying the coating onto the components
made of nonferrous metal is performed by application of a Zn dust
mixture at a temperature in the range of 300 to 600.degree. C. with
formation of a zinc diffusion layer.
[0018] The nonferrous metal alloys selected according to the
present invention are well-used substrates for the application of
Zn coatings in form of a zinc diffusion coating. Zn is suited for
formation of well-adhering metal alloys or intermediate phases. It
is provided that the transition between the substrate metal and the
zinc of the coating is not abrupt but, instead, takes place via
Zn/metal intermediate phases or alloys.
[0019] The substrate materials are also distinguished in that the
zinc diffusion coating will not cause a formation of brittle
Zn/metal intermediate phases. This is important for application in
vehicle components because, in the further processing stages, the
coated components will be subjected to partially massive mechanical
stresses or further deformation which could cause brittle coatings
to flake off. The Zn coating applied according to the present
invention and, respectively, the edge region of the component will
thus form, together with the substrate, a (relative to the
substrate hardness) ductile and closed connection.
[0020] When used in connection with a component made of titanium or
titanium alloys, the method of the present invention has the
advantage that poisonous and environmentally harmful cadmium can be
replaced by the zinc thermodiffusion layer as a coating material
for protection from corrosion in contact with steel alloys.
[0021] Special commercial relevance should be attributed to the use
of the zinc thermodiffusion method in aluminum or aluminum alloys.
For example, for the copper-containing or stress-crack-prone Al
alloys, there can thus be provided an inexpensive alternative to
plating with pure Al or, for example, AlZnl. This is of relevance
for bodies in aircraft construction.
[0022] According to an embodiment of the present invention, the
metal surface can be cleaned of oxides prior to the Zn coating
process according to the zinc thermodiffusion process. By means of
this cleaning process, an additional activation of the metal
surface can be effected. Cleaning can be performed by mechanical or
chemical means.
[0023] According to an embodiment of the present invention, the
Zn-diffusion-coated non-ferrous metallic components, for example,
being light metal vehicle-body components comprising Al, are
provided with a phosphating coating as normally used for corrosion
protective treatment of steels. On the surface of the light metal
component, such as an aluminum component, there can be obtained,
after phosphating, the same process parameters for the subsequent
application of organic covering layers (lacquers, such as KTL
coatings) as in other zinc-coated components. The
mixed-construction components can therefore be processed together
after joining.
[0024] A further advantage of the zinc diffusion coating resides in
the improved adhesion of the surface in organic coatings, lacquers,
adhesives or the like.
[0025] The zinc diffusion layer also provides an excellent basis
for structural bonding, for example, for spot-weld bonding,
punch-rivet bonding or blind-rivet bonding. The zinc diffusion
layer provides good contact protection in places where nonferrous
metal and steel are in mutual abutment without an adhesive.
[0026] According to an embodiment of the present invention, the
nonferrous-metal component is formed as a metal sheet and, after
the coating process, is further shaped by deep drawing. The Zn
layers generated by the coating method used according to the
present invention adhere so strong and yet so ductile that they can
endure a deep drawing process without suffering damage. This holds
true, for example, for Al light metal alloys.
[0027] The light metal components on the basis of Al-, Ti- or
Mg-alloys, which have been coated by the Zn thermodiffusion method,
can also be subjected to further treatment by thermoforming. In
this regard, it is significant that the thermoforming can be
performed in air instead of in a protective gas. The need for a
protective gas atmosphere in the furnace is thus obviated. By the
Zn coating, the highly oxidation-prone light metals are protected
from ingress of air and from oxidation.
[0028] A further aspect of the present invention is that the zinc
thermodiffusion layer is useful as a lubricant replacement suitable
for hot forming. The use of lubricants for the forming tools can
therefore be reduced.
[0029] The maximum heating temperature for the Zn-coated
semi-finished metal sheet of nonferrous metal should be below the
melting point of zinc. An advantage of thermal forming compared to
the conventional cold deep-drawing is an improved dimensional
stability of the components. The thermal forming of the light
metals can be carried out in an inexpensive manner by the
Zn-thermodiffusion coating.
[0030] An aspect of the present invention relates to vehicle body
components, for example, for automobiles, in metal hybrid
construction or mixed construction, wherein at least one light
metal component and a component made of steel are joined to each
other. The light metal component provided with a zinc
thermodiffusion layer (zinc diffusion layer) prevents a direct
contact between the light metal and the steel in the joint
region.
[0031] For the present invention, the surface of the light metal
component should be covered by a zinc diffusion layer. In the joint
regions, the contact to the component made of steel is thus
effected via the zinc diffusion layer, and a direct contact between
the light metal and the steel is avoided.
[0032] The voltage drop between the different metal alloys is
thereby lowered, and the tendency to corrosion of the less precious
partner is considerably reduced.
[0033] Components which are to be connected are frequently joined
to each other with a mutual overlap, resulting in the formation of
a thin gap between the components. In a vehicle body, such a gap is
frequently exposed to electrolyte-containing water which bridges
the two components in an electrically conducting manner. The
generated local elements can thus lead to damaging corrosion
phenomena. The usual methods for the sealing of joints or by the
KTL (cathodic dip coating or cathaphoretic dip coating), the gap
region is frequently not reliably coated or sealed. Therefore, it
is still possible that water (for example, condensed water or
splash water) and other electrolyte-containing carrier liquids can
intrude into this gap, with the consequential risk of contact
corrosion. Exactly this corrosion, which is much feared in the
joining gap, can advantageously be effectively reduced via the zinc
diffusion coating of the light metal component.
[0034] According to an embodiment of the present invention, the
vehicle body component can be coated by a lacquer at least in the
region of the joining area. For example, in this regard, a KTL
coating is of relevance. The coating can be applied onto the Zn
layer of the light metal component. It is also possible to first
apply a corrosion protection primer, such as a phosphating layer,
and to apply the lacquer layer upon the primer layer.
[0035] For the steel component of the mixed-construction component,
use can, for example, be made of zinc-coated steel. In this case,
the steel can be provided with the usual zinc coatings. For
instance, the structural component made of metal can be formed from
hot-galvanized sheet metal, for example, by strip galvanizing,
wherein sheet metal can be continuously drawn through a bath of
molten zinc. A zinc layer protecting the steel from corrosion is
thus formed on both sides of the metal sheet.
[0036] The steel component can additionally be provided with a
corrosion protection primer, optionally on a Zn coating, prior to
the joining with the Zn-coated light metal component. Also in this
context, a suitable connection technology can reside in using
normal thermal and mechanical joining methods as well as bonding.
Steel bands with corrosion protection primer are suitable for
welding by the usual welding methods.
[0037] It is a particulate advantage of the Zn thermodiffusion
coating of the light metal component that, with regard to further
coatings or lacquers to be applied later, this layer will behave in
nearly the same manner as the surface of a zinc-coated steel
component. Thus, the mixed-construction component can be subjected
to further treatment in common surface-treatment or surface-coating
processes. For example, in the Zn-thermodiffusion-coated (Al) light
metal components, the pickling for removing the Al-oxide layer and
the application of a conversion layer for subsequent further
manufacturing process steps, such a bonding or KTL coating, can be
eliminated. The precoated semifinished products can be processed in
a similar manner to zinc-coated sheet metal--from deep-drawing and
joining up to lacquering processes.
[0038] The production of aluminum sheet-metal components by use of
pre-coated semifinished products made of aluminum sheet-metal is
also facilitated or made possible by equipment which is typically
designed or optimized for steel sheet metal.
[0039] After phosphating as a pretreatment for subsequent organic
cover layers, the same process parameters can be obtained on the
surface of the light metal component as in other zinc-coated
components. For example, the zinc thermodiffusion layer is also
conductive and thus weldable and suitable for a subsequent coating
with RTL.
[0040] In case of a light-metal or steel components or sheets, the
present vehicle body component of the mixed-construction type is
joined, in the joining regions between the light metal and the
steel or the iron alloy, for example, by use of rivet connections
without additional bonding.
[0041] The vehicle body components are useful especially for
automobiles, rail vehicles and aircraft.
[0042] The present invention is not limited to embodiments
described herein; reference should be had to the appended
claims.
* * * * *